Dioxane substituted amides

ABSTRACT

This invention discloses new compounds of the formula ##STR1## WHEREIN R 1  is selected from the group consisting of hydrogen and alkyl; X is halogen; R 2  is selected from the group consisting of alkyl, alkenyl and alkynyl; n is the integer 1 or 2; Z is alkyl; and m is an integer from 0 to 4. Further disclosed are herbicidal compositions utilizing the aforedescribed compounds.

This invention relates to new compositions of matter and more specifically relates to new chemical compounds of the formula ##STR2## wherein R¹ is selected from the group consisting of hydrogen and alkyl; X is halogen; R² is selected from the group consisting of alkyl, alkenyl and alkynyl; n is the integer 1 or 2; Z is alkyl; and m is an integer from 0 to 4.

The compounds of the present invention are useful as herbicides and are exceptionally suitable as preemergence grass herbicides. Moreover the subject compounds are useful for stunting the growth of ornamental turf reducing the need for mowing.

In a preferred embodiment of the present invention R¹ is selected from the group consisting of hydrogen and lower alkyl; X is selected from the group consisting of chlorine and bromine; R² is selected from the group consisting of alkyl of up to ten carbon atoms, lower alkenyl and lower alkynyl; n is the integer 1 or 2; Z is lower alkyl and m is an integer from 0 to 2.

The term lower as used herein designates a straight or branched carbon chain of up to six carbon atoms.

The compounds of the present invention can be prepared by reacting a compound of the formula ##STR3## wherein R², n, Z and m are as heretofore described, with an α-haloalkanoyl chloride of the formula ##STR4## wherein R¹ and X are as heretofore described. This reaction can be effected by combining a compound of formula II with an about equimolar or slight excess molar amount of a compound of formula III in an inert organic reaction medium, such as benzene, in the presence of an acid acceptor, such as an alkali metal carbonate or bicarbonate or a tertiary amine, at a temperature of about -10° C. to about 25° C. and stirring the resulting mixture for a period of from about 15 to about 120 minutes. After this time the reaction mixture can be washed with water to remove inorganic salts and stripped of solvent to yield the desired product. This product can then be used as such or can be further purified by conventional means.

The compounds of formula II can be prepared by reacting a substituted amine of the formula ##STR5## wherein R² is as heretofore described with a compound of the formula ##STR6## wherein Y is chlorine or bromine and n, Z and m are as heretofore described. This reaction can be effected by combining the compound of formula V with an excess molar amount of the amine of formula IV and heating the mixture with agitation for a period of from 1/2 to 8 hours. When a very low boiling amine is used a pressurized vessel can be preferably utilized. After this time strong inorganic base such as aqueous sodium hydroxide is added to the reaction mixture to liberate the free amine from its hydrochloride. The organic phase is then separated from the aqueous phase, dried over anhydrous magnesium sulfate and distilled to yield the desired product.

The compounds of formula V when not avaiable can be prepared by reacting an acetal of the formula ##STR7## wherein Y and n are as heretofore described and R³ and R⁴ are methyl or ethyl, with a diol of the formula ##STR8## wherein R⁵, R⁶, R⁷, R⁸, R⁹ and R¹⁰ are hydrogen or alkyl, provided a maximum of four of R⁵, R⁶, R⁷, R⁸, R⁹ and R¹⁰ are alkyl. This reaction can be effected by combining the compound of formula VI with the compound of formula VII in about equimolar amounts and in the presence of an acid catalyst such as sulfuric acid or toluene sulfonic acid under anhydrous conditions. The mixture can be heated for a period of from about 1 to about 4 hours to remove the alcohol that is formed. After this time the reaction mixture can be distilled under reduced pressure to yield the desired product.

The compounds of the present invention can also be prepared by reacting an acetal of the formula ##STR9## wherein R¹, X, R², n, R³ and R⁴ are as heretofore described with an about equimolar amount of the diol of formula VII. This reaction can be effected by combining the reactants in the presence of a catalytic amount of toluene sulfonic acid under anhydrous conditions. The reaction mixture can be heated and the alcohol removed by distillation as it is formed. After no more alcohol is given off sodium carbonate can be added and the reaction mixture distilled to yield the desired product.

The compounds of formula VIII can be prepared by reacting a compound of the formula ##STR10## wherein R², n, R³ and R⁴ are as heretofore described, with a compound of formula III. This reaction can be effected in the same manner as the reaction between compound II and III described above.

The compounds of formula IX can be prepared by reacting the amine of formula IV with an about equimolar amount of the acetal of formula VI. This reaction can be effected by combining the reactants in an inert organic reaction medium in the presence of an acid acceptor. The reaction mixture can be heated at reflux for a period of from 2 to 24 hours. After this time the mixture is filtered and stripped of solvent to yield the desired product.

Exemplary suitable diols of formula VII for preparing the compounds of the present invention are propandiol-1,3, butandiol-1,3, pentandiol-1,3, hexandiol-1,3, heptandiol-1,3, octandiol-1,3, pentandiol-2,4, hexandiol-2,4, octandiol-2,4, octandiol-3,5, 2-methylbutandiol-1,3 and the like.

Exemplary suitable amines of formula IV are methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, allylamine, 2-butenylamine, 2-pentenylamine, 3-pentenylamine, 4-hexenylamine, 5-hexenylamine, proparygylamine, 2-butynylamine, 3-butynylamine, 1,1-dimethylpropargylamine, 1,1-diethylpropargylamine, 4-hexynylamine, isopropylamine, t-butylamine and the like.

Exemplary suitable α-haloalkanoyl chlorides of formula III for preparing the compounds of this invention are chloroacetyl chlorides, α-chloropropanoyl chloride, α-bromobutanoyl chloride, α-chloropentanoyl chloride, α-chlorohexanoyl chloride, α-chloro-α-methylbutanoyl chloride, α-chloroheptanoyl chloride and the like.

EXAMPLE 1 Preparation of the Diethylacetal of 2-Isopropylaminoacetaldehyde

The diethylacetal of 2-bromoacetaldehyde (118 grams) and isopropylamine (260 ml) were charged into a Parr Shaker. The shaker was sealed and heated with an infra-red lamp with agitation to a pressure of about 50 p.s.i. Heating was then stopped and the mixture was shaken for an additional 30 minutes. After this time aqueous sodium hydroxide (90 ml; 50% concentration) was added to the reaction mixture with stirring. The organic phase was separated from the aqueous phase, was dried and distilled under reduced pressure to yield the desired product the diethylacetal of 2-isopropylaminoacetaldehyde as the residue.

EXAMPLE 2 Preparation of N-Isopropyl-N-(2,2-diethoxyethyl)-α-chloroacetamide

The diethylacetal of 2-isopropylaminoacetaldehyde (68 grams), benzene (100 ml), water (100 ml) and sodium carbonate (44 grams) were charged into a glass reaction vessel equipped with a mechanical stirrer and thermometer. The reaction mixture was cooled to a temperature of 5° to 10° C. and chloroacetyl chloride (30 ml) was added dropwise with stirring. Stirring was continued until the reaction mixture reached room temperature. After this time the organic phase was separated from the aqueous phase, was washed with water and dried over anhydrous magnesium sulfate. The dried solution was filtered and the filtrate stripped of solvent to yield the desired product N-isopropyl-N-(2,2-diethoxyethyl)-α-chloroacetamide as the residue.

EXAMPLE 3 Preparation of N-Isopropyl-N-(1,3-dioxan-2-ylmethyl)-α-chloroacetamide

N-Isopropyl-N-(2,2-diethoxyethyl)-α-chloroacetamide (10 grams), propandiol-1,3 (2.9 ml) and trace amounts of toluenesulfonic acid were charged into a glass reaction vessel equipped with a mechanical stirrer, thermometer and reflux condenser. The reaction mixture was heated until no more ethanol was given off. After this time sodium carbonate (1 gram) was added to the mixture with stirring and the resulting mixture was distilled to yield the desired product N-isopropyl-N-(1,3-dioxan-2-ylmethyl)-α-chloroacetamide having a boiling point of 165° C. at 1.0 mm of Hg pressure.

EXAMPLE 4 Preparation of N-Isopropyl-N-(5,5-dimethyl-1,3-dioxan-2-ylmethyl)-α-chloroacetamide

N-Isopropyl-N-(2,2-diethoxyethyl)-α-chloroacetamide (10 grams), 2,2-dimethylpropandiol-1,3 (4.1 grams) and trace amounts of toluenesulfonic acid were charged into a glass reaction vessel equipped with a mechanical stirrer, thermometer and reflux condenser. The reaction mixture was heated until no more ethanol was given off. After this time sodium carbonate (1 gram) was added to the mixture with stirring and the resulting mixture was distilled to yield the desired product N-isopropyl-N-(5,5-dimethyl-1,3-dioxan-2-ylmethyl)-α-chloroacetamide having a boiling point of 175° C. at 1 mm of Hg pressure.

EXAMPLE 5 Preparation of the Diethylacetal of 2-Allylaminoacetaldehyde

The diethylacetal of 2-bromoacetaldehyde (118 grams) and allylamine (250 ml) are charged into a Parr Shaker. The shaker is sealed and heated with an infra-red lamp, with agitation, to a pressure of about 50 p.s.i. Heating is then stopped and the mixture is shaken for an additional 30 minutes. After this time aqueous sodium hydroxide (90 ml; 50% concentration) is added to the reaction mixture with stirring. The organic phase is then separated from the aqueous phase, is dried and is distilled under reduced pressure to yield the desired product the diethylacetal of 2-allylaminoacetaldehyde.

EXAMPLE 6 Preparation of N-Allyl-N-(2,2-diethoxyethyl)-α-chloroacetamide

The diethylacetal of 2-allylaminoacetaldehyde (50 grams), benzene (100 ml), water (100 ml) and sodium carbonate (40 grams) are charged into a glass reaction vessel equipped with a mechanical stirrer and thermometer. The reaction mixture is cooled to a temperature of 5° to 10° C. and chloroacetyl chloride (30 ml) is added dropwise with stirring. Stirring is continued until the reaction mixture reaches room temperature. After this time the organic phase is separated from the aqueous phase, is washed with water and dried over anhydrous magnesium sulfate. The dried solution is filtered and stripped of solvent to yield the desired product N-allyl-N-(2,2-diethoxyethyl)-α-chloroacetamide.

EXAMPLE 7 Preparation of N-Allyl-N-(1,3-dioxan-2-ylmethyl)-α-chloroacetamide

N-Allyl-N-(2,2-diethoxyethyl)-α-chloroacetamide (10 grams), propandiol-1,3 (3 ml) and trace amounts of toluenesulfonic acid are charged into a glass reaction vessel equipped with a mechanical stirrer, thermometer and reflux condenser. The reaction mixture is heated until no more ethanol is given off. After this time sodium carbonate (1 gram) is added to the mixture with stirring and the resulting mixture is distilled to yield the desired product N-allyl-N-(1,3-dioxan-2-ylmethyl)-α-chloroacetamide.

EXAMPLE 8 Preparation of the Diethylacetal of 2-Propargylaminoacetaldehyde

The diethylacetal of 2-bromoacetaldehyde (118 grams) and propargylamine (250 ml) are charged into a Parr Shaker. The shaker is sealed and heated with an infra-red lamp, with agitation, to a pressure of about 50 p.s.i. Heating is then stopped and the mixture is shaken for an additional 30 minutes. After this time aqueous sodium hydroxide (90 ml; 50% concentration) is added to the reaction mixture with stirring. The organic phase is then separated from the aqueous phase, is dried and is distilled under reduced pressure to yield the desired product the diethylacetal of 2-propargylaminoacetaldehyde.

EXAMPLE 9 Preparation of N-Propargyl-N-(2,2-diethoxyethyl)-α-chloroacetamide

The diethylacetal of 2-propargylaminoacetaldehyde (50 grams), benzene (100 ml), water (100 ml) and sodium carbonate (40 grams) are charged into a glass reaction vessel equipped with a mechanical stirrer and thermometer. The reaction mixture is cooled to a temperature of 5° to 10° C. and chloroacetyl chloride (30 ml) is added dropwise with stirring. Stirring is continued until the reaction mixture reaches room temperature. After this time the organic phase is separated from the aqueous phase, is washed with water and dried over anhydrous magnesium sulfate. The dried solution is filtered and stripped of solvent to yield the desired product N-propargyl-N-(2,2-diethoxyethyl)-α-chloroacetamide.

EXAMPLE 10 Preparation of N-Propargyl-N-(1,3-dioxan-2-ylmethyl)-α-chloroacetamide

N-Propargyl-N-(2,2-diethoxyethyl)-α-chloroacetamide (10 grams), propandiol-1,3 (3 ml) and trace amounts of toluenesulfonic acid are charged into a glass reaction vessel equipped with a mechanical stirrer, thermometer and reflux condenser. The reaction mixture is heated until no more ethanol is given off. After this time sodium carbonate (1 gram) is added to the mixture with stirring and the resulting mixture is distilled to yield the desired product N-propargyl-N-(1,3-dioxan-2-ylmethyl)-α-chloroacetamide.

EXAMPLE 11 Preparation of the Diethylacetal of 2-Methylaminoacetaldehyde

The diethylacetal of 2-bromoacetaldehyde (118 grams) and methylamine (250 ml) are charged into a Parr Shaker. The shaker is sealed and heated with an infra-red lamp, with agitation, to a pressure of about 50 p.s.i. Heating is then stopped and the mixture is shaken for an additional 30 minutes. After this time aqueous sodium hydroxide (90 ml; 50% concentration) is added to the reaction mixture with stirring. The organic phase is then separated from the aqueous phase, is dried and is distilled under reduced pressure to yield the desired product the diethylacetal of 2-methylaminoacetaldehyde.

EXAMPLE 12 Preparation of N-Methyl-N-(2,2-diethoxyethyl)-α-bromoacetamide

The diethylacetal of 2-methylaminoacetaldehyde (50 grams), benzene (100 ml), water (100 ml) and sodium carbonate (40 grams) are charged into a glass reaction vessel equipped with a mechanical stirrer and thermometer. The reaction mixture is cooled to a temperature of 5° to 10° C. and bromoacetyl chloride (30 ml) is added dropwise with stirring. Stirring is continued until the reaction mixture reaches room temperature. After this time the organic phase is separated from the aqueous phase, is washed with water and dried over anhydrous magnesium sulfate. The dried solution is filtered and stripped of solvent to yield the desired product N-methyl-N-(2,2-diethoxyethyl)-α-bromoacetamide.

EXAMPLE 13 Preparation of N-Methyl-N-(1,3-dioxan-2-ylmethyl)-α-bromoacetamide

N-Methyl-N-(2,2-diethoxyethyl)-α-bromoacetamide (10 grams), propandiol-1,3 (3 ml) and trace amounts of toluenesulfonic acid are charged into a glass reaction vessel equipped with a mechanical stirrer, thermometer and reflux condenser. The reaction mixture is heated until no more ethanol is given off. After this time sodium carbonate (1 gram) is added to the mixture with stirring and the resulting mixture is distilled to yield the desired product N-methyl-N-(1,3-dioxan-2-ylmethyl)-α-bromoacetamide.

EXAMPLE 14 Preparation of the Diethylacetal of 2-Ethylaminoacetaldehyde

The diethylacetal of 2-bromoacetaldehyde (118 grams) and ethylamine (250 ml) are charged into a Parr Shaker. The shaker is sealed and heated with an infra-red lamp, with agitation, to a pressure of about 50 p.s.i. Heating is then stopped and the mixture is shaken for an additional 30 minutes. After this time aqueous sodium hydroxide (90 ml; 50% concentration) is added to the reaction mixture with stirring. The organic phase is then separated from the aqueous phase, is dried and is distilled under reduced pressure to yield the desired product the diethylacetal of 2-ethylaminoacetaldehyde.

EXAMPLE 15 Preparation of N-Ethyl-N-(2,2-diethoxyethyl)-α-bromopropionamide

The diethylacetal of 2-ethylaminoacetaldehyde (50 grams), benzene (100 ml), water (100 ml) and sodium carbonate (40 grams) are charged into a glass reaction vessel equipped with a mechanical stirrer and thermometer. The reaction mixture is cooled to a temperature of 5° to 10° C. and α-bromopropionyl chloride (30 ml) is added dropwise with stirring. Stirring is continued until the reaction mixture reaches room temperature. After this time the organic phase is separated from the aqueous phase, is washed with water and dried over anhydrous magnesium sulfate. The dried solution is filtered and stripped of solvent to yield the desired product N-ethyl-N-(2,2-diethoxyethyl)-α-bromopropionamide.

EXAMPLE 16 Preparation of N-Ethyl-N-(1,3-dioxan-2-ylmethyl)-α-bromopropionamide

N-Ethyl-N-(2,2-diethoxyethyl)-α-bromoproprionamide (10 grams), propandiol-1,3 (3 ml) and trace amounts of toluenesulfonic acid are charged into a glass reaction vessel equipped with a mechanical stirrer, thermometer and reflux condenser. The reaction mixture is heated until no more ethanol is given off. After this time sodium carbonate (1 gram) is added to the mixture with stirring and the resulting mixture is distilled to yield the desired product N-ethyl-N-(1,3-dioxan-2-ylmethyl)-α-bromoproprionamide.

Additional compounds with the scope of the present invention which can be prepared by the procedures of the foregoing examples are further exemplified by the following:

N-methyl-N-(4-methyl-1,3-dioxan-2-ylmethyl)-α-chloroacetamide, N-ethyl-N-(4-ethyl-1,3-dioxan-2ylmethyl)-α-chloroacetamide, N-propyl-N-(5-propyl-1,3-dioxan-2-ylmethyl)-α-chloroacetamide, N-butyl-N-(5-butyl-1,3-dioxan-2-ylmethyl)-α-chloroacetamide, N-pentyl-N-(5-pentyl-1,3-dioxan-2-ylmethyl)-α-chloroacetamide, N-hexyl-N-(5-hexyl-1,3-dioxan-2-ylmethyl)-α-chloroacetamide, N-allyl-N-(4,5-dimethyl-1,3-dioxan-2-ylmethyl)-α-chloroacetamide, N-but-3-enyl-N-(4,5,6-trimethyl-1,3-dioxan-2-ylmethyl)-α-chloroacetamide, N-pent-4-enyl-N-(5-ethyl-1,3-dioxan-2-ylethyl)-α-bromobutanamide, N-hex-4-enyl-N-(5-ethyl-1,3-dioxan-2-ylethyl)-α-chlorobutanamide, N-but-3-ynyl-N-(5-ethyl-1,3-dioxan-2-ylethyl)-α-iodopentanamide, N-pent-3-ynyl-N-(5-ethyl-1,3-dioxan-2-ylethyl)-α-chlorohexanamide, N-hex-4-ylyl-N-(5-ethyl-1,3-dioxan-2-ylethyl)-α-chloroheptanamide.

For practical use as herbicides the compounds of this invention are generally incorporated into herbicidal compositions which comprise an inert carrier and a herbicidally toxic amount of such a compound. Such herbicidal compositions, which can also be called formulations, enable the active compound to be applied conveniently to the site of the weed infestation in any desired quantity. These compositions can be solids such as dusts, granules, or wettable powders; or they can be liquids such as solutions, aerosols, or emulsifiable concentrates.

For example, dusts can be prepared by grinding and blending the active compound with a solid inert carrier such as the talcs, clays, silicas, pyrophyllite, and the like. Granular formulations can be prepared by impregnating the compound, usually dissolved in a suitable solvent, onto and into granulated carriers such as the attapulgites or the vermiculites, usually of a particle size range of from about 0.3 to 1.5 mm. Wettable powders, which can be dispersed in water or oil to any desired concentration of the active compound, can be prepared by incorporating wetting agents into concentrated dust compositions.

In some cases the active compounds are sufficiently soluble in common organic solvents such as kerosene or xylene so that they can be used directly as solutions in these solvents. Frequently, solutions of herbicides can be dispersed under super-atmospheric pressure as aerosols. However, preferred liquid herbicidal compositions are emulsifiable concentrates, which comprise an active compound according to this invention and as the inert carrier, a solvent and an emulsifier. Such emulsifiable concentrates can be extended with water and/or oil to any desired concentration of active compound for application as sprays to the site of the weed infestation. The emulsifiers most commonly used in these concentrates are nonionic or mixtures of nonionic with anionic surface-active agents. With the use of some emulsifier systems an inverted emulsion (water in oil) can be prepared for direct application to weed infestations.

A typical herbicidal composition according to this invention is illustrated by the following example, in which the quantities are in parts by weight.

EXAMPLE 17 Preparation of a Dust

    ______________________________________                                         Product of Example 3      10                                                   Powdered Talc             90                                                   ______________________________________                                    

The above ingredients are mixed in a mechanical grinder-blender and are ground until a homogeneous, free-flowing dust of the desired particle size is obtained. This dust is suitable for direct application to the site of the weed infestation.

The compounds of this invention can be applied as herbicides in any manner recognized by the art. One method for the control of weeds comprises contacting the locus of said weeds with a herbicidal composition comprising an inert carrier and as an essential active ingredient, in a quantity which is herbicidally toxic to said weeds, a compound of the present invention. The concentration of the new compounds of this invention in the herbicidal compositions will vary greatly with the type of formulation and the purpose for which it is designed, but generally the herbicidal compositions will comprise from about 0.05 to about 95 percent by weight of the active compounds of this invention. In a preferred embodiment of this invention, the herbicidal compositions will comprise from about 5 to about 75 percent by weight of the active compound. The compositions can also comprise such additional substances as other pesticides, such as insecticides, nematocides, fungicides, and the like; stabilizers, spreaders, deactivators, adhesives, stickers, fertilizers, activators, synergists, and the like.

The compounds of the present invention are also useful when combined with other herbicides and/or defoliants, dessicants, growth inhibitors, and the like in the herbicidal compositions heretofore described. These other materials can comprise from about 5% to about 95% of the active ingredients in the herbicidal compositions. Use of combinations of these other herbicides and/or defoliants, dessicants, etc., with the compounds of the present invention provide herbicidal compositions which are more effective in controlling weeds and often provide results unattainable with separate compositions of the individual herbicides. The other herbicides, defoliants, dessicants and plant growth inhibitors, with which the compounds of this invention can be used in the herbicidal compositions to control weeds, can include chlorophenoxy herbicides such as 2,4-D, 2,4,5-T, MCPA, MCPB, 4(2,4-DB), 2,4-DEB, 4-CPB, 4-CPA, 4-CPP, 2,4,5-TB, 2,4,5-TES, 3,4-DA, silvex and the like; carbamate herbicides such as IPC, CIPC, swep, barban, BCPC, CEPC, CPPC, and the like; thiocarbamate and dithiocarbamate herbicides such as CDEC, metham sodium, EPTC, diallate, PEBC, perbulate, vernolate and the like; substituted urea herbicides such as norea, siduron, dichloral urea, chloroxuron, cycluron, fenuron, monuron, monuron TCA, diuron, linuron, monolinuron, neburon, buturon, trimeturon and the like; symmetrical triazine herbicides such as simazine, chlorazine, atraone, desmetryne, norazine, ipazine, prometryn, atrazine, trietazine, simetone, prometone, propazine, ametryne and the like; chloroacetamide herbicides such as alpha-chloro-N,N-dimethylacetamide, CDEA, CDAA, alpha-chloro-N-isopropylacetamide, 2-chloro-N-isopropylacetanilide, 4-(chloroacetyl)morpholine, 1-(chloroacetyl)piperidine and the like; chlorinated aliphatic acid herbicides such as TCA, dalapon, 2,3-dichloropropionic acid, 2,2,3-TPA and the like; chlorinated benzoic acid and phenylacetic acid herbicides such as 2,3,6-TBA, 2,3,5,6-TBA, dicamba, tricamba, amiben, fenac, PBA, 2-methoxy-3,6-dichlorophenylacetic acid, 3-methoxy-2,6-dichlorophenylacetic acid, 2-methoxy-3,5,6-trichlorophenylacetic acid, 2,4-dichloro-3-nitrobenzoic acid and the like; and such compounds as aminotriazole, maleic hydrazide, phenyl mercuric acetate, endothal, biuret, technical chlordane, dimethyl 2,3,5,6-tetrachloroterephthalate, diquat, erbon, DNC, DNBP, dichlobenil, DPA, diphenamid, dipropalin, trifluralin, solan, dicryl, merphos, DMPA, DSMA, MSMA, potassium azide, acrolein, benefin, bensulide, AMS, bromacil, 2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione, bromoxynil, cacodylic acid, CMA, CPMF, cypromid, DCB, DCPA, dichlone, diphenatril, DMTT, DNAP, EBEP, EXD, HCA, ioxynil, IPX, isocil, potassium cyanate, MAA, MAMA, MCPES, MCPP, MH, molinate, NPA, OCH, paraquat, PCP, picloram, DPA, PCA, pyrichlor, sesone, terbacil, terbutol, TCBA, brominil, CP-50144, H-176-1, H-732, M-2901, planavin, sodium tetraborate, calcium cyanamid, DEF, ethyl xanthogen disulfide, sindone, sindone B, propanil and the like. Such herbicides can also be used in the methods and compositions of this invention in the form of their salts, esters, amides, and other derivatives whenever applicable to the particular parent compounds.

Weeds are undesirable plants growing where they are not wanted, having no economic value, and interfering with the production of cultivated crops, with the growing of ornamental plants, or with the welfare of livestock. Many types of weeds are known, including annuals such as pigweed, lambsquarters, foxtail, crabgrass, wild mustard, field pennycress, ryegrass, goose grass, chickweed, wild oats, valvet-leaf, purslane, barnyardgrass, smartweed, knotweed, cocklebur, wild buckwheat, kochia, medic, corn cockle, ragweed, sow-thistle, coffeeweed, croton, cuphea, dodder, fumitory, groundsel, hemp nettle, knawel, spurge, spurry, emex, jungle rice, pondweed, dog fennel, carpetweed, morningglory, bedstraw, ducksalad, naiad, cheatgrass, fall panicum, jimsonweed, witchgrass, switchgrass, watergrass, teaweed, wild turnip and sprangletop; biennials such as wild carrot, matricaria, wild barley, campion, chamomile, burdock, mullein, round-leaved mallow, bull thistle, hounds-tongue, moth mullein and purple star thistle; or perennials such as white cockle, perennial ryegrass, quackgrass, Johnsongrass, Canada thistle, hedge bindweed, Bermuda grass, sheep sorrel, curly dock, nutgrass, field chickweed, dandelion, campanula, field bindweed, Russian knapweed, mesquite, toadflax, yarrow, aster, gromwell, horsetail, ironweed, sesbania, bulrush, cattail, winter-cress, horsenettle, nutsedge, milkweed and sicklepod.

Similarly, such weeds can be classified as broad-leaf or grassy weeds. It is economically desirable to control the growth of such weeds without damaging beneficial plants or livestock.

The new compounds of this invention are particularly valuable for weed control because they are toxic to many species and groups of weeds. The exact amount of compound required will depend on a variety of factors, including the hardiness of the particular weed species, weather, type of soil, method of application, the kind of beneficial plants in the same area and the like. Thus, while the application of up to only about one or two ounces of active compound per acre may be sufficient for good control of a light infestation of weeds growing under adverse conditions, the application of 10 pounds or more of an active compound per acre may be required for good control of a dense infestation of hardy perennial weeds growing under favorable conditions.

The herbicidal toxicity of the new compounds of this invention can be illustrated by many of the established testing techniques known to the art, such as pre- and post-emergence testing.

The herbicidal activity of the compounds of this invention was demonstrated by experiments carried out for the pre-emergence control of a variety of weeds. In these experiments small plastic greenhouse pots filled with dry soil were seeded with the various weed seeds. Twenty-four hours or less after seeding the pots were sprayed with water until the soil was wet and the test compounds formulated as aqueous emulsions of acetone solutions containing emulsifiers were sprayed at the indicated concentrations on the surface of the soil.

After spraying, the soil containers were placed in the greenhouse and provided with supplementary heat as required and daily or more frequent watering. The plants were maintained under these conditions for a period of 21 days, at which time the condition of the plants and the degree of injury to the plants was rated on a scale of from 0 to 10, as follows: 0 = no injury, 1,2 = slight injury, 3,4 = moderate injury, 5,6 = moderately severe injury, 7,8,9 = severe injury and 10 = death. The effectiveness of these compounds is demonstrated by the data in Table I.

                                      TABLE I                                      __________________________________________________________________________     Test                                                                               Rate                                                                       Com-                                                                               (lbs/-                                                                            Weed Species                                                            pound                                                                              acre)                                                                             YNSG                                                                               WOAT                                                                               JMWD VTLF                                                                               JNGS                                                                               PIGW                                                                               WMSTD                                                                               YLFX                                                                               BNGS                                                                               CBGS                                                                               CTGS                                                                               MNGY PDWD                 __________________________________________________________________________     Pro-                                                                           duct of                                                                            8  4    10 4    6   5    10 4    9   10  9    10 0    --                   Ex. 3                                                                              2  2   3   2    3   3    10 4    6   10   10  10 0    --                       1  0   0   0    0   0   0   4    3   10  2   0   0    --                   Pro-                                                                           duct of                                                                            8   10 0   0    4   9   0   0    9   10  9   2   3    --                   Ex. 4                                                                              2  2   0   0    0   4   0   0    6   1   7   1   0    --                       1  2   0   0    0   2   0   0    1   0   2   0   0    --                   __________________________________________________________________________                 YNSG = Yellow Nutsedge  WMSTD = Wild Mustard                                   WOAT =  Wild Oats        YLFX = Yellow Foxtail                                 JMWD = Jimsonweed        BNGS = Barnyardgrass                                  VTLF = Velvetleaf        CBGS = Crabgrass                                      JNGS = Johnsongrass     CTGS = Cheatgrass                                      PIGW = Pigweed          MNGY = Wild Morningglory                                                       BDWD = Bindweed                            __________________________________________________________________________

The herbicidal activity of the compounds of this invention was also demonstrated by experiments carried out for the post-emergence control of a variety of weeds. In these experiments the compounds to be tested were formulated as aqueous emulsions and sprayed at the indicated dosage on the foliage of the weeds that have attained a prescribed size. After spraying, the plants were placed in a greenhouse and watered daily or more frequently. Water was not applied to the foliage of the treated plants. The severity of the injury was determined 14 days after treatment and was rated on the scale of from 0 to 10 heretofore described. The effectiveness of these compounds is demonstrated by the data in Table II.

                                      TABLE II                                     __________________________________________________________________________     Test                                                                               Rate                                                                       Com-                                                                               (lbs/-                                                                            Weed Species                                                            pound                                                                              acre)                                                                             YNSG                                                                               WOAT                                                                               JMWD VTLF                                                                               JNGS                                                                               PIGW                                                                               WMSTD                                                                               YLFX                                                                               BNGS                                                                               CBGS                                                                               CTGS                                                                               MNGY BDWD                 __________________________________________________________________________     Pro-                                                                           duct of                                                                            8  2   4   0    --  3   0   2    4   8   7   --  2    0                    Ex. 3                                                                              2  0   3   0    --  0   0   0    4   5   6   --  0    0                        1  0   0   0    --  2   0   4    2   7   3   --  0    0                    Pro-                                                                           duct of                                                                            8  --  3   3    --  4   0   3    6   4   5   --  3    4                    Ex. 4                                                                              2  --  0   0    --  0   0   0    2   2   3   --  0    0                        1  --  0   0    --  0   0   0    4   0   1   --  0    0                    __________________________________________________________________________                 YNSG = Yellow Nutsledge WMSTD = Wild Mustard                                   WOAT =  Wild Oats        YLFX = Yellow Foxtail                                 JMWD = Jimsonweed        BNGS = Barnyardgrass                                  VTLF = Velvetleaf        CBGS = Crabgrass                                      JNGS = Johnsongrass      CTGS = Cheatgrass                                     PIGW = Pigweed           MNGY = Wild Morningglory                                                       BDWD = Bindweed                           __________________________________________________________________________ 

What is claimed is:
 1. A compound of the formula ##STR11## wherein R¹ is selected from the group consisting of hydrogen and alkyl; X is halogen; R² is selected from the group consisting of alkyl, alkenyl and alkynyl; n is the integer 1 or 2; Z is alkyl; and m is an integer from 0 to
 4. 2. The compound of claim 1, N-isopropyl-N-(1,3-dioxan-2-ylmethyl)-α-chloroacetamide.
 3. The compound of claim 1, N-isopropyl-N-(5,5-dimethyl-1,3-dioxan-2-ylmethyl)-α-chloroacetamide
 4. The compound of claim 1, N-allyl-N-(1,3-dioxan-2-ylmethyl)-α-chloroacetamide.
 5. The compound of claim 1, N-propargyl-N-(1,3-dioxan-2-ylmethyl)-α-chloroacetamide.
 6. The compound of claim 1, N-methyl-N-(1,3-dioxan-2-ylmethyl)-α-bromoacetamide.
 7. The compound of claim 1, N-ethyl-N-(1,3-dioxan-2-ylmethyl)-α-bromopropionamide.
 8. A herbicidal composition comprising an inert carrier and, as an essential active ingredient, a herbicidally effective amount of a compound of claim
 1. 9. A method of controlling weeds which comprises contacting said weeds with an effective amount of a herbicidal composition of claim
 8. 